Heretofore, there have been known various methods for generating random numbers, such as a method using a computer to generate random numbers on a software basis, and a method using a counter or the like to generate pseudo random numbers. These random numbers generated by the conventional methods cannot be regarded as authentic random numbers, and it can only be evaluated how close the random numbers are to authentic random numbers. For example, a conventional method for such an evaluation comprises acquiring a large number of values which are generated as random numbers through a large-scale computer, and checking respective occurrence distributions of the acquired values to evaluate how evenly each of the values occurs, on the basis of the occurrence distributions. This evaluation method premised on acquiring a large number of values and checking respective occurrence distributions of the values essentially requires a long time to obtain an evaluation result.
Under the circumstance where random numbers are increasingly being used for various simulations—for example, in the fields of financial derivatives, strength simulations for buildings, weather forecasts and simulation-based advanced game machines—a random number generation device to be used in these fields is required to generate extremely authentic random numbers at a high speed. For a random number generation device meeting such requirements, a random number generation method utilizing a random natural phenomenon has been proposed.
In recent years, a random number generation device has become known which is designed to generate random numbers using thermal noise occurring inside a resistor, a conductor or a semiconductor, as means for realizing the above natural phenomenon-based random number generation method. In view of its advantage of being able to have a relatively simple circuit configuration, this random number generation device is expected to allow substantially authentic random numbers to be conveniently used in various fields.
In a process of producing and shipping the random number generation device in/from a production plant, it is necessary to inspect whether the apparatus normally operates, before the shipment. Further, when the random number generation device is installed in various commercial products or incorporated in an IC card or the like in the form of an IC chip, the apparatus after shipment is likely to have a malfunction, or to undergo a malicious or wrongful manipulation intended, for example, to intentionally increase or reduce an occurrence frequency of a specific value. Thus, it is necessary to develop a method or means for quickly detecting such abnormalities. However, as to a random number generation device designed to generate substantially authentic random numbers, no method capable of readily/reliably detecting the occurrence of abnormalities, such as malfunctions and wrongful manipulations, has been established so far.
In view of the above technical background, it is therefore an object of the present invention to provide a random number verification method and apparatus capable of quickly/reliably detect that a random number generation device designed to generate substantially authentic random numbers has become unable to generate authentic random numbers due to a malfunction, wrongful manipulation or the like.